Key/Samhongsa cab forwards

[ATSF_Ron]

Chris333, that's a sweet one!  How did it run?  I've also been looking for an AC-4.  They're tough to find at reasonable prices.  BTW, I like your layout build threads, especially the Erie/Mahoning layout.  I'm planning a similar arrangement in a spare room but with a SoCal feel using mostly SP/ATSF equipment.  I feel like the staging area will enhance operations.  How has that worked for you?

[Chris333]

I only confirmed that it ran to sell. Put it on the track, turned up the throttle and it moved, put it in the box lol. Some guy at a show was practically begging me to buy it.

Staging is always good, but I rarely get a chance to play trains lately.

[ATSF_Ron]

Bummer, Chris.  I'm recently retired, so I have time to play! And get frustrated, lol!


I had some interesting observations today on types of track.  I put away the Unitrack semi-loop and played around with some Atlas and Peco code 55 with turnouts.  What happened was the opposite of what I expected.  The loco was smooth as silk with the code 55 Atlas, even without the frog feeder wire.  No binding or hesitation.  This was a #7 turnout.  Idk what the diverging radius is, but it looked and performed flawlessly.  With the Peco, it was fine on the mainline route, but it stalled on the diverging route as the rear tender truck approached the frog.  Again, I didn't have the frog wire connected to anything.  Other than that, it was flawless.  Neither type of turnout had the loco riding up and over the frog, as I've had some Bachmann and BLI steamers do.  Whichever type of track I decide to go with I'm definitely powering the frog as I have on my other sections of the layout.  I've often struggled with Atlas as the code 55 switches are so damn temperamental, so I decided to buy some Peco.  ALL of the Peco Unifrogs have been stellar with zero problems, unlike their Electrofrogs, which take some massaging.  Like many others, I prefer the look of the Atlas code 55 turnouts (with Micro engineering flextrack) but HATE all the finagling I have to do with at least half the damned things to get them to function properly.  Hence, my decision to replace them, and most of the track, with Peco code 55.  All you Fastracks fans please don't lobby for building my own.  I don't have the patience or desire for that!  And honestly, once ballasted my 62 year old eyes can accept the Peco tie spacing.

I also was able to get rid of the clicking sound this loco had on turns.  The forward driver set has some kind of appliance under the firebox next to the front driver on each side.  The engineer's side looked a bit bent inward to me, so I took a fingernail and coaxed it out a tiny bit.  Problem solved!

Next up is getting the track plan finalized on the new section and revamping the whole thing to operate and fit better into my available space!

[robert3985]

Bummer, Chris.  I'm recently retired, so I have time to play! And get frustrated, lol!


I had some interesting observations today on types of track.  I put away the Unitrack semi-loop and played around with some Atlas and Peco code 55 with turnouts.  What happened was the opposite of what I expected.  The loco was smooth as silk with the code 55 Atlas, even without the frog feeder wire.  No binding or hesitation.  This was a #7 turnout.  Idk what the diverging radius is, but it looked and performed flawlessly.  With the Peco, it was fine on the mainline route, but it stalled on the diverging route as the rear tender truck approached the frog.  Again, I didn't have the frog wire connected to anything.  Other than that, it was flawless.  Neither type of turnout had the loco riding up and over the frog, as I've had some Bachmann and BLI steamers do.  Whichever type of track I decide to go with I'm definitely powering the frog as I have on my other sections of the layout.  I've often struggled with Atlas as the code 55 switches are so damn temperamental, so I decided to buy some Peco.  ALL of the Peco Unifrogs have been stellar with zero problems, unlike their Electrofrogs, which take some massaging.  Like many others, I prefer the look of the Atlas code 55 turnouts (with Micro engineering flextrack) but HATE all the finagling I have to do with at least half the damned things to get them to function properly.  Hence, my decision to replace them, and most of the track, with Peco code 55.  All you Fastracks fans please don't lobby for building my own.  I don't have the patience or desire for that!  And honestly, once ballasted my 62 year old eyes can accept the Peco tie spacing.

I also was able to get rid of the clicking sound this loco had on turns.  The forward driver set has some kind of appliance under the firebox next to the front driver on each side.  The engineer's side looked a bit bent inward to me, so I took a fingernail and coaxed it out a tiny bit.  Problem solved!

Next up is getting the track plan finalized on the new section and revamping the whole thing to operate and fit better into my available space!

First off, it may be an inopportune time to start buying Peco55 as Peco is in the process of developing a line of "American Profile" Code55 track, including both turnouts and flextrack.  Secondly, Micro Engineering has drawings of #8 and #10 turnouts on their boards, and after they've got their HO trackage replenished and they are moved into their facilities, it's assumed they'll be expanding their N-scale track line.

If ME's new turnouts offer cast frogs and hinged point rails like their #6's, then it might be worth it to wait a while.

If Peco can get its head out of the "N-gauge has to look like a toy" thought process and simplify their new "American Profile" Code55 N-scale trackage so it actually looks like North American prototype trackage instead of some ultra cut-down, complicated Bizarro World trackage, following their HO scale American style trackage, then it would be worth the wait too...with no need to have out-of-proportion ties assault your eyes for the rest of your layout's life.

An important point about N-scale turnouts.  If some engines run smoothly on any turnout, but others don't, the problem is most likely that the engines that aren't running well (hopping) have drivers and/or wheelsets that are out of gauge.  My experience with purchasing a variety of steam and diesel N-scale locomotives over the past 40+ years is that I've only had two types of engines be properly gauged our of the box...my Kato FEF3's and my LikMore GS2's.  Everything else had at least one wheelset that needed adjustment to run smoothly through my NMRA compliant hand-built turnouts.   

Since when I build my turnouts on my workbench, I constantly check the gauge of the trackage being soldered to the PCB ties (all part of the construction process) I am positive when my turnouts are finished that they are fully compliant with NMRA recommended practices.  However, I am not so positive when I buy turnouts for customers' layouts and modules, so every turnout that I buy gets checked with my trusty NMRA Standards Gage before I install them.  Then, I know if there's a problem with an engine going through it, it's the engine's fault, not the turnout's.

I also check the gauge on each and every engine before running it on the layout...before even putting it on the layout.  It's hard to understand what is so difficult about getting the spacing between the flanges correct, but very few manufacturers seem to be able to do it consistently.

As for what the effective diverging radius of an Atlas #7 is, it is incorrect...much smaller than what an equivalent prototype #7 turnout would be.  Atlas drastically shortens all of their turnouts between the frog and the throwbar so they'll fit into their sectional track product line with no need for short track adapters.  This isn't a functional problem with their #7's, #10's, Wyes and Curved Turnouts, but the smaller radius was and IS a problem with their #5's because the diverging radius is closer to a #4 and many engines and cars that will negotiate a "true" #5 turnouts, will derail on a #4.

When comparing scaled-down prototype turnout drawings to various manufacturers' products, the most accurate is the Micro Engineering #6 (hopefully their future turnouts will be equally properly constructed).  Peco55's tracks are close to being properly proportioned, but their ties are horribly out of proportion.  Atlas55 turnouts are all drastically too short, even though their tie spacing looks better than Peco55's...with their turnouts being properly proportioned ahead of the frog, but waaaay too short from the frog to the throwbar...meaning the diverging radius has to compensate for that shortness by being a sharper radius.

Atlas55 has other problems too...which include plated "mystery metal" frogs, point rails and guard rails...and the plating wears off after a while because of track cleaning, revealing a copper plating...which wears off revealing whatever metal the parts are made from. 

Both Peco55 and ME Code55 turnouts manage to make their turnout rails out of nickel-silver without any apparent unsolvable technical problems.  Why Atlas55 can't do the same is a good question.

Yup.  Dead frogs are anathema to smooth running through turnouts, mainly because of bad turnout design with the dead frogs being too long.  I have experimented with dead frogs in the past, and short ones on smaller turnouts work just fine, but when the turnouts get larger than #6, the frogs should be wired up.  Of course, some engines have bad electrical pickup as part of their poor design and need fixing before they'll run through dead frogs.

Anyway, have fun!

Bob Gilmore

[ATSF_Ron]

Thanks for all that track info, Bob. I had no idea about the Peco or Micro Engineering future offerings. I may end up waiting, but given the timeline of most N scale manufacturing, I’d rather get my layout built while I’m still above ground! Haha! Do you have any idea of the timeline on these? I haven’t seen anything in the model railroad press.

[robert3985]

Thanks for all that track info, Bob. I had no idea about the Peco or Micro Engineering future offerings. I may end up waiting, but given the timeline of most N scale manufacturing, I’d rather get my layout built while I’m still above ground! Haha! Do you have any idea of the timeline on these? I haven’t seen anything in the model railroad press.

Hey Ron, unfortunately, I don't have any solid info on timelines for either ME's or Peco's track offerings.  There are several threads here at TRW about both, with photos of the Peco booth at the latest National NMRA Show where Peco had a sales rep and an engineer there with 3D printed "American Profile" pre-production samples, which didn't look all that good to me.

ME news is from various conversations customers have had with people at ME and news articles about them being in the process of moving to a new facility after being purchased...with notification that their HO track line has priority, but "drawings" are on the board for N-scale #8 & #10 Code55 turnouts...which would be immensely welcomed into the N-scale community.

I'm 74 this year, and my next 20' of portable sections for my layout will be laid with Code55 and Code40 rails on 3D printed tie strips, even though I have a big cache of old Rail Craft Code55 flex which 20' of new layout sections will only make a slight dent in my hoard.

I just want to have the most realistic-looking track I can manage before I board that Streamliner into my final sunset....

Will it be worth the extra effort and time?  It'll satisfy an itch I've had for decades wishing that somebody would produce quality, prototypical looking N-scale track I could use on my modules and layout...so, yup, it's worth it to me! I'll just make my own! 

Cheerio!
Bob Gilmore

[ATSF_Ron]

I've run the AC-6 for about an hour on my Unitrack test oval.  It definitely like the clockwise direction better (right turns), even at 19" radius.  It slows down slightly in curves when going counterclockwise (left turns).  I took the small bottom plates off and lubed the gears the day I got it and that helped smooth out the running and quieted things down.  But...I feel it can be better,possibly, with more lube higher up in the loco.  I reread Mark's (Spookshow) review and shudder to think about removing the shell off this puppy.  Do you think the driving shaft and couplings will benefit from lube?  From Mark's photo with the shell off, I don't see any more gears exposed other than what I saw removing the small bottom plates/covers.  When I lubed I also left the loco upside down for a bit to let gravity do its thing with the oil.  Have I lubed it enough?  All gearing is metal, if that makes any difference.

[ATSF_Ron]

I decided to be adventurous or stupid, or maybe it's a little of both!  I opened her up and took out both sets of drivers.  Well, almost both.  The rear set was easy enough.  The front set was almost out but kept hanging up on something.  I suspect it may have been the lighting.  I believe the prior owner installed a headlight, as I think these were not delivered with factory lighting from Samhongsa.  At any rate, I was able to get the front engine set out far enough to access what needed lube.  Now comes the fun part...putting it all back!  Mark (Spookshow) wasn't kidding when he said it was a nightmare to reassemble.  After several attempts, I decided to make this post to give my nerves (and temper!) a break.  Wish me luck!  Hopefully the lubing quiets things down some more.

In the last pic you can see how tiny the washers are that need to go under the screws!  They might be 2mm in diameter.  Yikes!  It's a miracle I didn't lose any.

[robert3985]

Good luck with that reassembly!

Cheerio!
Bob Gilmore

[ATSF_Ron]

So here's a couple observations for any of you who may have one of these or a similar loco with a similar drive from Samhongsa. 

1.  In the last pic there's a long bar that has a screw which goes in each end.  This bar connects the two "engines" or driver sets underneath.  I believe it's also supposed to be an extra electrical connection.  You can see the wire dangling off the screw on the right side.  It's supposed to be connected to the screw on the left side.  As I had the loco upside down and began to follow Spookshow Mark's directions for disassembly, I noticed the screw on the left had a broken solder connection.  I immediately put it back on the track and test ran it, thinking maybe I broke the connection accidentally.  Nope.  It ran exactly the same as before.  So apparently the wire doesn't serve any purpose.  Maybe it's a backup?  Or maybe the current flows through the connecting bar as well.  I have no idea.  Anyhow, I got it all put back together post-lube and she runs like a dream, comparatively speaking.  If the running quality pre disassembly was a C+ then it's now a B+.  I'm completely satisfied.  The noise level is also MUCH much better.

2.  In the last pic again there's a very large diameter screw on the far left.  This is one of the screws that releases the front driver set from the shell, and it mounts directly under the connecting bar I was just talking about.  When reassembling, if you tighten it too much I noticed that it will twist the front steam cylinder chest (I hope that's the right term) out of alignment and can potentially cause binding of the valve gear during running.  I played around with the tightness/alignment of the cylinder chest and tested it out.  Any remaining binding or surging I had in "left turns" (counterclockwise in a circle of track) are now 100% GONE.  I'm a happy camper!

Is this as quiet and smooth as an Intermountain unit? No.  But given that NO ONE is making any older AC cab forwards with none on the horizon, I'm very satisfied with my purchase.  Some lube, a little experimental tweaking, and a good running in have made a world of difference.  This loco will be a regular on my layout as I get the next section with larger radius curves completed.

[Mike Madonna]

Hi Ron,
You are to be commended for "digging into" one of these beauties. I found an AC-5 (Late version) last year. It had a DZ143 Digitrax decoder installed. The loco test ran "OK". My intention was to install a Loksound V5 "Nano" sound decoder. But first, I wanted to disassemble and thoroughly clean the driveline including the gear towers/boxes, side rods (also their alignment, as there was a slight "bind") as well as the entire loco. It appears to have lived a not "pampered" life (numerous items either bent/broke and several bare brass spots on the boiler/cab). These locos are really not that difficult to disassemble/re-assemble, if you "take a few notes". I included some photos I took on my "notes". My "notes" are shallow empty boxes (empty Dimi-Trains drop-bottom gondola boxes/lids) with a picture of the loco driveline taped to the bottom. Then I took double sided tape and "stick" the screw/washer/etc. in the correct position. I did the same for the tender as well. So, I know EXACTLY where the screw/washer goes AND it does not get lost. The loco was put on the "back burner" due to the unavailability of the V5 Nano for some time. I now have the decoder (and speaker). The plan is to put both in the smoke box cover.

[ATSF_Ron]

Mike, nice work on the AC5!  That's a smart move using the tape and boxes.  I'm stealing that idea.  I have my eye on an AC4 but would really like the AC5 as well.  Then I'll have all 3 of the "early" cab aheads.  My AC6 clearly lived a pampered life.  I wonder if it ever even had much track time.  The loco, tender, box and foam are all mint!  From everything I've read, these can be quite temperamental.  I guess I got lucky with mine.  My success with this one has given me confidence to try again with my Pecos River 4-6-2.  I was getting pretty pissed off and frustrated at my lack of progress, so I parked that project for a few months.  I even had it up for sale for a bit but decided to keep it.  Hopefully I can fix the short.  It's been a bit of a bi$%! to work through.